Problem: Simplify the following expression: $x = \dfrac{-6k}{3} + \dfrac{-6k}{3}$
Explanation: Since the expressions have the same denominator we simply combine the numerators: $x = \dfrac{-6k - 6k}{3}$ Combine like terms: $x = \dfrac{-12k}{3}$ Simplify by dividing numerator and denominator by 3: $x = \dfrac{-4k}{1}$ $x = -4k$